1. Field of the Invention
This invention relates generally to ramps for use between a pair of surfaces of different elevation to facilitate transporting cargo from one of the surfaces to the other of the surfaces, and more particularly to ramps used to load and unload cargo from a vehicle trailer.
2. Related Art
When transporting numerous and/or heavy containers, generally, a large semi trailer, or the like, is used, and commonly, ramps are use to facilitate loading and removing the containers into and from the trailer. The ramps are typically built integrally into the trailer, and are pulled out from a rear portion of the trailer for use, and pushed back into the trailer for storage. These ramps can prove difficult to use when the tracks along which they slide become corroded, and from their being generally large, heavy and cumbersome. Otherwise, when the trailer does not have a built-in ramp, commonly, portable ramps are used. The portable ramps are typically formed having a single piece load support surface extending between one end arranged for attachment to the transport vehicle, and another end arranged for abutment with a ground surface. Some of these ramps are commonly constructed with nubs extending upwardly from the support surface to facilitate maintaining traction with the load surface in use. Unfortunately, when the nubs become worn, they are unable to be replaced, and thus, the ramp can become slippery after extended use. As a result, the ramp typically must be replaced with a new ramp.